<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>手写Promise返回的类型约束</title>
  </head>
  <body></body>
  <script src="js/Hd.js"></script>
  <script>
    let promise = new Hd((resolve, reject) => {
      resolve();
    });
    let p = promise.then((value) => {
      return p;
    });
  </script>
</html>
